Method of fabricating semiconductor package having an interposer structure

ABSTRACT

A method of fabricating a semiconductor package is provided, including: cutting a substrate into a plurality of interposers; disposing the interposers in a plurality of openings of a carrier, wherein the openings are spaced from one another by a distance; forming a first encapsulant to encapsulate the interposers; removing the carrier; and disposing at least a semiconductor element on each of the interposers. By cutting the substrate first, good interposers can be selected and rearranged such that finished packages can be prevented from being wasted due to inferior interposers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of copending application U.S. Ser. No.13/722,017, filed on Dec. 20, 2012, which claims under 35 U.S.C. §119(a)the benefit of Taiwanese Application No. 101132953, filed Sep. 10, 2012,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to semiconductor packages, and, moreparticularly, to a semiconductor package having through silicon vias(TSV), a method of fabricating the semiconductor package, and aninterposer structure of the semiconductor package.

2. Description of Related Art

Flip-chip technologies facilitate to reduce chip packaging sizes andshorten signal transmission paths and therefore have been widely usedfor chip packaging. Various types of packages, such as chip scalepackages (CSP), direct chip attached (DCA) packages and multi-chipmodule (MCM) packages, can be achieved through flip-chip technologies.

In a flip-chip packaging process, a great coefficient of thermalexpansion (CTE) mismatch between a chip and a packaging substrateadversely affects the formation of joints between conductive bumps ofthe chip and contacts of the packaging substrate, thus likely resultingin delamination of the conductive bumps from the packaging substrate. Onthe other hand, along with increased integration of integrated circuits,a CTE mismatch between a chip and a packaging substrate induces morethermal stresses and leads to more serious warpage, thereby reducing theproduct reliability and resulting in failure of a reliability test.

To overcome the above-described drawbacks, a silicon interposer isdisposed between a semiconductor chip and a packaging substrate. Sincethe silicon interposer and the semiconductor chip are made of similarmaterials, the above-described drawbacks caused by a CTE mismatch can beeffectively prevented.

FIGS. 1A to 1C show a method of fabricating a conventional semiconductorpackage 1.

Referring to FIG. 1A, a plurality of TSVs 100 are formed in a siliconinterposer 10, and a redistribution layer (RDL) structure (not shown) isformed on an upper side of the silicon interposer 10. A plurality ofsemiconductor chips 11 are disposed on the upper side of the siliconinterposer 10 and electrically connected to the TSVs 100 through aplurality of conductive bumps 110.

Referring to FIG. 1B, an encapsulant 12 is formed on the siliconinterposer 10 to encapsulate the semiconductor chips 11, thereby forminga plurality of packages 1 a.

Referring to FIG. 1C, an RDL structure 13 is formed on a lower side ofthe silicon interposer 10 according to the practical need, and then asingulation process is performed to obtain a plurality of singulatedpackages 1 a. Each of the packages 1 a is disposed on and electricallyconnected to a packaging substrate 15 through a plurality of conductivebumps 14.

However, forming the through silicon vias 100 in the silicon interposer10 results in a high fabrication cost. Further, according to the processyield, some units 10′ of the silicon interposer 10 may be inferior.Although a good semiconductor chip 11 can be selected by performing anelectrical performance test after a singulation process, the goodsemiconductor chip 11 may be disposed on an inferior unit 10′. As such,the finished package 1 a cannot pass a reliability test, andconsequently the good semiconductor chip 11 must be wasted along withthe inferior unit 10′, thereby increasing the fabrication cost.

On the other hand, if inferior units 10′ are detected before forming theencapuslant 12 so as to avoid disposing of good semiconductor chips 11on the inferior units 10′, it will become difficult to control theamount and flow path of the encapsulant 12. Consequently, thesemiconductor chips 11 cannot be evenly covered by the encapsulant 12.

In addition, since the silicon interposer 10 is not singulated beforedisposing the semiconductor chips 11 on the silicon interposer 10, thesemiconductor chips 11 are required to be less in size than thecorresponding units 10′, such that the number of the electrodes of thesemiconductor chips 11 is limited. Consequently, the module function andefficiency of the units 10′ are limited.

Therefore, how to overcome the above-described drawbacks has becomeurgent.

SUMMARY OF THE INVENTION

In view of the above-described drawbacks, the present invention providesa semiconductor package, which comprises: a first encapsulant; aninterposer embedded in the first encapsulant, wherein the interposer hasopposite first and second surfaces, side surfaces connected to theopposite first and second surfaces, and a plurality of conductivethrough holes penetrating the first and second surfaces, each of theconductive through holes having a first end at the first surface and asecond end opposite to the first end, and the side surfaces of theinterposer being covered by the first encapsulant; and at least asemiconductor element disposed on and electrically connected to thefirst surface of the interposer.

The present invention further provides a method of fabricating asemiconductor package, which comprises: providing a substrate havingopposite first and second surfaces and a plurality of conductive throughholes penetrating the first surface, wherein each of the conductivethrough holes has a first end at the first surface and a second endopposite to the first end; cutting the substrate into a plurality ofinterposers, wherein each of the interposers has side surfacesconnecting the first and second surfaces thereof; disposing theinterposers on a carrier through the first surfaces thereof, wherein thecarrier has a plurality of openings so as for the interposers to bedisposed therein and the openings are spaced from one another by adistance; forming a first encapsulant on the carrier so as to cover theside surfaces of the interposers and encapsulate the interposers;removing the carrier; and disposing and electrically connecting at leasta semiconductor element to the first surface of each of the interposers.

In an embodiment, the first surface of each of the interposers furtherhas a plurality of conductive elements electrically connected to thefirst ends of the conductive through holes, and the conductive elementsare disposed in a corresponding one of the openings of the carrier.After the carrier is removed, the semiconductor element is bonded andelectrically connected to the conductive elements.

In an embodiment, the method further comprises forming an adhesive inthe openings of the carrier so as to bond the interposers to thecarrier.

In an embodiment, the method, after disposing the semiconductor elementon the interposer, further comprises performing a singulation process soas to form a plurality of semiconductor packages.

In an embodiment, the first surface of the interposer further has aredistribution layer (RDL) structure so as for the semiconductor elementto be disposed thereon and electrically connected to the first ends ofthe conductive through holes through the RDL structure.

In an embodiment, an RDL structure are formed on the second surface ofthe interposer and electrically connected to the second ends of theconductive through holes.

In an embodiment, the semiconductor element and the first ends of theconductive through holes of the interposer are electrically connectedthrough a plurality of conductive elements.

In an embodiment, the conductive elements protrude above the firstencapsulant.

In an embodiment, a second encapsulant is further formed on the firstencapsulant for encapsulating the semiconductor element.

In an embodiment, one side of the semiconductor element opposite to theinterposer is exposed from the second encapsulant.

In an embodiment, the method further comprises removing a portion of theinterposer so as to expose the second ends of the conductive throughholes of the interposer.

The present invention further provides an interposer structure, whichcomprises: an encapsulant; and an interposer embedded in theencapsulant, wherein the interposer has opposite first and secondsurfaces, side surfaces connected to the opposite first and secondsurfaces, and a plurality of conductive through holes penetrating thefirst and second surfaces, each of the conductive through holes having afirst end at the first surface and a second end opposite to the firstend, and the side surfaces of the interposer being covered by theencapsulant.

In an embodiment, the first surface of the interposer is flush with asurface of the encapsulant.

In an embodiment, the second surface of the interposer and the secondends of the conductive through holes are covered by the encapsulant.

In an embodiment, the second surface of the interposer and the secondends of the conductive through holes are exposed from the encapsulant.

In an embodiment, the second surface of the interposer and the secondends of the conductive through holes are flush with a surface of theencapsulant.

In an embodiment, the interposer structure further comprises an RDLstructure formed on the first surface of the interposer and electricallyconnected to the first ends of the conductive through holes. In anembodiment, a plurality of conductive elements are formed on the RDLstructure and protrude above the encapsulant. In an embodiment, the RDLstructure is flush with a surface of the encapsulant.

In an embodiment, the interposer structure further comprises a pluralityof conductive elements formed on the first surface of the interposer andprotruding above the encapsulant.

In an embodiment, the interposer structure further comprises an RDLstructure formed on the second surface of the interposer andelectrically connected to the second ends of the conductive throughholes.

Therefore, by cutting the substrate first, good interposers can beselected and rearranged in the openings of the carrier so as for goodsemiconductor elements to be disposed thereon. As such, finishedpackages can be prevented from being wasted due to inferior interposers,thereby reducing the fabrication cost.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A to 1C are cross-sectional views showing a method of fabricatinga conventional semiconductor package;

FIGS. 2A to 2H are cross-sectional views showing a method of fabricatinga semiconductor package according to a first embodiment of the presentinvention, wherein FIG. 2A′ is an upper view of FIG. 2A;

FIGS. 3A to 3C are cross-sectional views showing a method of fabricatinga semiconductor package according to a second embodiment of the presentinvention, wherein FIGS. 3A′ and 3B′ shows another embodiment of FIGS.3A and 3B; and

FIGS. 4A to 4C are cross-sectional views showing an interposer structureaccording to different embodiments of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following illustrative embodiments are provided to illustrate thedisclosure of the present invention, these and other advantages andeffects can be apparent to those in the art after reading thisspecification.

It should be noted that all the drawings are not intended to limit thepresent invention. Various modification and variations can be madewithout departing from the spirit of the present invention. Further,terms, such as “first”, “second”, “upper”, “lower”, “a” etc., are merelyfor illustrative purpose and should not be construed to limit the scopeof the present invention.

FIGS. 2A to 2H are cross-sectional views showing a method of fabricatinga semiconductor package 2 according to a first embodiment of the presentinvention.

Referring to FIGS. 2A and 2A′, a substrate 20 having a first surface 20a and a second surface 20 b opposite to the first surface 20 a isprovided. A plurality of conductive through holes 200 are formed in thesubstrate 20 and penetrating the first surface 20 a. Each of theconductive through holes 200 has a first end 200 a exposed from thefirst surface 20 a of the substrate 20 and a second end 200 b oppositeto the first end 200 a.

In an embodiment, the substrate 20 is a wafer or othersilicon-containing material. If needed, a redistribution layer (RDL)structure 201 can be formed on the first surface 20 a of the substrate20 and electrically connected to the first ends 200 a of the conductivethrough holes 200.

In an embodiment, a plurality of conductive elements 202 are furtherformed on the RDL structure 201 and electrically connected to the firstends 200 a of the conductive through holes 200 directly or through theRDL structure 201.

The conductive elements 202 are metal bumps such as copper bumps with asolder material formed thereon.

Referring to FIG. 2B, the substrate 20 is cut along a cutting path S (asshown in FIGS. 2A and 2A′) so as to form a plurality of interposers 20′.Each of the interposers 20′ has side surfaces 20 c connecting the firstand second surfaces 20 a, 20 b.

A carrier 3 having a plurality of openings 30 is provided, and theinterposers 20′ are disposed in the openings 20 of the carrier 3 throughthe first surfaces 20 a thereof. The openings 30 are spaced from oneanother by a distance D.

In an embodiment, the distance D is greater than the width t of thecutting path S.

The conductive elements 202 of each of the interposers 20′ are disposedin the corresponding opening 30 of the carrier 3, and an adhesive 31 isformed in the opening 30 to bond with the interposer 20′ and encapsulatethe conductive elements 202, thereby fixing the interposer 20′ to thecarrier 3.

The conductive elements 202 can be, but not limited to, bumps or posts.

Referring to FIG. 2C, a first encapsulant 22 is formed on the carrier 3to cover the side surfaces 20 c of the interposers 20′ and encapsulatethe interposers 20′, thereby forming a package 2 a.

Referring to FIG. 2D, the carrier 3 is removed so as for the conductiveelements 202 to protrude above the surface of the first encapsulant 22.

Referring to FIG. 2E, one or more semiconductor elements 21 are disposedon the first surface 20 a of each of the interposers 20′.

In an embodiment, the semiconductor element 21 is a chip and has anactive surface 21 a and a non-active surface 21 b opposite to the activesurface 21 a. The semiconductor element 21 is disposed on the conductiveelements 202 through the active surface 21 a thereof and electricallyconnected to the RDL structure 201 of the interposer 20′ or the firstends 200 a of the conductive through holes 200 through the conductiveelements 202.

In another embodiment, the conductive elements 202 are disposed on thesemiconductor element 21 instead of the RDL structure 201. After thecarrier 3 is removed, the semiconductor element 21 is disposed on thefirst surface 20 a of the interposer 20′ through the conductive elements202.

Further, the active surface 21 a of the semiconductor element 21 can bedirectly bonded to the first surface 20 a of the interposer 20′ or theRDL structure 201 instead of through the conductive elements 202.

Referring to FIG. 2F, a second encapsulant 23 is formed on the firstencapsulant 22 to encapsulate the semiconductor elements 21 and theconductive elements 202.

In an embodiment, an upper portion of the second encapsulant 23 isremoved by grinding such that the non-active surface 21 b of thesemiconductor element 21 is flush with an upper surface of the secondencapsulant 23. As such, the non-active surface 21 b of thesemiconductor element 21 is exposed from the second encapsulant 23.

The non-active surface 21 b of the semiconductor element 21 is exposedfrom the second encapsulant 23 for heat dissipation.

Referring to FIG. 2G a lower portion of the first encapsulant 22 and alower portion of the interposer 20′ are removed so as for the lowersurface of the first encapsulant 22 and the second surface 20 b′ of theinterposer 20′ to be flush with the second ends 200 b of the conductivethrough holes 200, thereby exposing the second ends 200 b of theconductive through holes 200.

Referring to FIG. 2H, an RDL structure 24 is formed on the lower surfaceof the first encapsulant 22 and the second surface 20 b′ of theinterposer 20′ and electrically connected to the second ends 200 b ofthe conductive through holes 200.

Then, a plurality of conductive elements 25 such as solder balls areformed on the RDL structure 24, which allows an electronic device (notshown) such as a packaging substrate or a circuit board to be disposedthereon after a singulation process.

Subsequently, a singulation process is performed along a cutting path L(as shown in FIG. 2H) so as to obtain a plurality of semiconductorpackages 2.

FIGS. 3A to 3C are cross-sectional views showing a method of fabricatinga semiconductor package 2′ according to a second embodiment of thepresent invention.

The second embodiment differs from the first embodiment in that in thesecond embodiment the second encapsulant 23 is not formed.

Referring to FIG. 3A, continued from FIG. 2D, a protection film (notshown) is formed to cover the conductive elements 202, and a lowerportion of the interposer 20′ and a lower portion of the firstencapsulant 22 are removed by grinding such that the second surface 20b′ of the interposer 20′ and the lower surface of the first encapsulant22 are flush with the second ends 200 b of the conductive through holes200, thereby exposing the second ends 200 b of the conductive throughholes 200.

Referring to FIG. 3B, an RDL structure 24 is formed on the secondsurface 20 b′ of the interposer 20′ and the lower surface of the firstencapsulant 22. Then, the protection film is removed and a semiconductorelement 21 is disposed on the conductive elements 202.

Referring to FIG. 3C, a plurality of conductive elements 25 are formedon the RDL structure 24 and then a singulation process is performed.

In another embodiment, referring to FIG. 3A′, continued from FIG. 2C,the interposer 20′ and the first encapsulant 22 are partially removed,and an RDL structure 24 and a plurality of conductive elements 25 areformed on the interposer 20′ and the first encapsulant 22. Then,referring to FIG. 3B′, the carrier 3 is removed and a semiconductorelement 21 is disposed on the interposer 20′. Subsequently, asingulation process is performed to form the structure of FIG. 3C.

By cutting the substrate 20 first, good interposers 20′ can be selectedand rearranged so as for good semiconductor elements 21 to be disposedthereon. Therefore, the present invention overcomes the conventionaldrawbacks and reduces the fabrication cost.

Further, by rearranging the interposers 20′ in the openings 30 of thecarrier 3, the present invention facilitates alignment of theinterposers and the carrier. Furthermore, since the distance D betweenthe interposers 20′ rearranged on the carrier is greater than theoriginal distance between the interposers 20′ on the substrate 20, i.e.,the width t of the cutting path S, the semiconductor elements 21 can begreater in size than the interposers 20′. Therefore, the number of theelectrodes of the semiconductor elements 21 can be increased accordingto the practical need so as to improve the module function andefficiency of the interposers 20′.

The present invention further provides a semiconductor package 2, 2′,which has: a first encapsulant 22, an interposer 20′ embedded in thefirst encapsulant 22 and a semiconductor element 21 disposed on thefirst encapsulant 22.

The interposer 20′ has opposite first and second surfaces 20 a, 20 b′and side surfaces 20 c connecting the opposite first and second surfaces20 a, 20 b′. The interposer 20′ further has a plurality of conductivethrough holes 200 penetrating the first and second surfaces 20 a, 20 b′.Each of the conductive through holes 200 has a first end 200 a exposedfrom the first surface 20 a and a second end 200 b opposite to the firstend 200 a. The side surfaces 20 c of the interposer 20′ are covered bythe first encapsulant 22.

The semiconductor element 21 has an active surface 21 a and a non-activesurface 21 b opposite to the active surface 21 a. The semiconductorelement 21 is disposed on and electrically connected to first surface 20a of the interposer 20′ through the active surface 21 a thereof.

The semiconductor package 2 further has a second encapsulant 23 formedon the first encapsulant 22 for encapsulating the semiconductor element21. The non-active surface 21 b of the semiconductor element 21 isexposed from the second encapsulant 23.

The semiconductor package 2, 2′ further has an RDL structure 24 formedon the first encapsulant 22 and the second surface 20 b′ of theinterposer 20′ and electrically connected to the second ends 200 b ofthe conductive through holes 200.

The semiconductor package 2, 2′ further has an RDL structure 201 formedbetween the semiconductor element 21 and the first surface 20 a of theinterposer 20′ and electrically connected to the first ends 200 a of theconductive through holes 200.

In an embodiment, the active surface 21 a of the semiconductor element21 and the first ends 200 a of the conductive through holes 200 areelectrically connected through a plurality of conductive elements 202.The conductive elements 202 protrude above the first encapsulant 22.

In an embodiment, the second surface 20 b′ of the interposer 20′ and thesecond ends 200 b of the conductive through holes 200 are exposed fromthe first encapsulant 22.

FIGS. 4A to 4C show an interposer structure 4, 4′, 4″ according todifferent embodiments of the present invention. The interposer structure4, 4′, 4″ has an encapsulant 42, 42′ and an interposer 40 embedded inthe encapsulant 42, 42′.

The interposer 40 has opposite first and second surfaces 40 a, 40 b andside surfaces 40 c connecting the first and second surfaces 40 a, 40 b.The interposer 40 further has a plurality of conductive through holes400 penetrating the first and second surfaces 40 a, 40 b. Each of theconductive through holes 400 has a first end 400 a exposed from thefirst surface 40 a and a second end 400 b opposite to the first end 400a.

The side surfaces 40 c of the interposer 40 are covered by theencapsulant 42, 42′.

The interposer structure 4, 4′, 4″ further has an RDL structure 401formed on the first surface 40 a of the interposer 40 and electricallyconnected to the first ends 400 a of the conductive through holes 400.

The interposer structure 4, 4′, 4″ further has a plurality of conductiveelements 402 formed on the first surface 40 a of the interposer 40 andprotruding above the encapsulant 42, 42′. In an embodiment, theconductive elements 402 are formed on the RDL structure 401.

In an embodiment, the RDL structure 401 is flush with the encapsulant42, as shown in FIG. 4A. In another embodiment, if no RDL structure 401is disposed on the first surface 40 a of the interposer 40, the firstsurface 40 a of the interposer 40 is flush with the encapsulant 42.Referring to FIGS. 4B and 4C, the RDL structure 401 (or the firstsurface 40 a of the interposer 40 and the first ends 400 a of theconductive through holes 400) can be covered by the encapsulant 42′.

In an embodiment, referring to FIG. 4A, the second surface 40 b of theinterposer 40 and the second ends 400 b of the conductive through holes400 are covered by the encapsulant 42.

In an embodiment, referring to FIG. 4B, the second surface 40 b of theinterposer 40 and the second ends 400 b of the conductive through holes400 are exposed from the encapsulant 42′. For example, the secondsurface 40 b of the interposer 40 and the second ends 400 b of theconductive through holes 400 are flush with the lower surface of theencapsulant 42′. Referring to FIG. 4C, the interposer structure 4″further has another RDL structure 44 formed on the second surface 40 bof the interposer 40 and the encapsulant 42′ and electrically connectedto the second ends 400 b of the conductive through holes 400.

Therefore, by cutting the substrate first, good interposers can beselected and rearranged in the openings of the carrier so as for goodsemiconductor elements to be disposed thereon. As such, finishedpackages can be prevented from being wasted due to inferior interposers,thereby reducing the fabrication cost.

The above-described descriptions of the detailed embodiments are only toillustrate the preferred implementation according to the presentinvention, and it is not to limit the scope of the present invention.Accordingly, all modifications and variations completed by those withordinary skill in the art should fall within the scope of presentinvention defined by the appended claims.

What is claimed is:
 1. A method of fabricating a semiconductor package,comprising: providing a substrate having opposite first and secondsurfaces and a plurality of conductive through holes penetrating thefirst surface, wherein each of the conductive through holes has a firstend at the first surface and a second end opposite to the first end;cutting the substrate into a plurality of interposers, wherein each ofthe interposers has side surfaces connected to first and second surfacesthereof; disposing the interposers on a carrier through the firstsurfaces thereof, wherein the carrier has a plurality of openings so asfor the interposers to be disposed therein and the openings are spacedfrom one another by a distance; forming a first encapsulant on thecarrier so as to cover the side surfaces of the interposers andencapsulate the interposers; removing the carrier; and disposing andelectrically connecting at least a semiconductor element to the firstsurface of each of the interposers.
 2. The method of claim 1, furthercomprising forming an adhesive in the openings of the carrier so as tobond the interposers to the carrier.
 3. The method of claim 1, whereinthe first surface of each of the interposers further has an RDLstructure so as for the semiconductor element to be disposed thereon andelectrically connected to the first ends of the conductive through holesthrough the RDL structure.
 4. The method of claim 1, wherein the firstsurface of each of the interposers further has a plurality of conductiveelements electrically connected to the first ends of the conductivethrough holes, and the conductive elements are disposed in acorresponding one of the openings of the carrier.
 5. The method of claim4, wherein the conductive elements protrude above the first encapsulantafter the carrier is removed.
 6. The method of claim 4, wherein thesemiconductor element is bonded and electrically connected to theconductive elements.
 7. The method of claim 1, wherein the semiconductorelement and the first ends of the conductive through holes of theinterposer are electrically connected through a plurality of conductiveelements.
 8. The method of claim 1, further comprising forming a secondencapsulant on the first encapsulant for encapsulating the semiconductorelement.
 9. The method of claim 8, further comprising removing a portionof the second encapsulant so as to expose one side of the semiconductorelement opposite to the interposer.
 10. The method of claim 8, furthercomprising removing a portion of the interposer so as to expose thesecond ends of the conductive through holes of the interposer.
 11. Themethod of claim 8, before or after removing the carrier, furthercomprising forming on the second surface of the interposer an RDLstructure that is electrically connected to the second ends of theconductive through holes of the interposer.
 12. The method of claim 1,further comprising removing a portion of the interposer so as to exposethe second ends of the conductive through holes of the interposer. 13.The method of claim 1, before or after removing the carrier, furthercomprising forming on the second surface of the interposer an RDLstructure that is electrically connected to the second ends of theconductive through holes of the interposer.
 14. The method of claim 1,after disposing the semiconductor element on the interposer, furthercomprising performing a singulation process so as to form a plurality ofsemiconductor packages.